Ultrashallow junctions for ULSI using As2+implantation and rapid thermal anneal

Using As₂⁺ ion implantation and rapid thermal anneal, 40-nm n⁺-p junctions are realized. The junction formed with p^- substrate shows very low leakage current (<0.5 nA/cm²) up to 2-V reverse bias. The introduction of a heavily doped (10¹⁸ cm^-3 level) p region generates a significantly higher leakage current due to the onset of band-to-band tunneling. Using varied geometry devices with a given area, the major tunneling current is shown to be confined in the perimeter of the device, and a method to suppress this leakage is suggested